I do think it's more of a tech thing. I believe it stems from valuing "culture fit" more than other industries do. I appreciate the idea of culture fit, but feel uneasy about it because it's also discriminatory and leads to problems like this.

I wonder if it's party because of the generalness and youngness of the industry. I imagine fields like oil rigging, therapy services for children, auto repair, or military service have more self-selecting cultures than building generic CRUD apps or web design for random clients.